“The value of turquoise comes from the quality and rarity of the stone,” write Emerald Tanner and her dad, Joe E. Tanner Sr., via email. The duo are at the helm of Tanner’s Indian Arts, a family-run store in Gallup, New Mexico, that’s been in business for over 60 years.

“Some mines produced tons of material over numbers of years,” they write. “Others, only a hundred or so pounds and for a very short period of time. Turquoise can be as soft as chalk or as hard as a 6 or 7 on Moh’s scale — the harder and more intense colors tend to be more valuable. Another variable in valuing turquoise is comparing all-natural turquoise to ‘stabilized’ or ‘enhanced’ turquoise.”

Turquoise Processing and Varieties

Turquoise is generally a naturally soft, porous stone that sustains damage in the cutting process — jewelers can only cut and shape the truly rare pieces without any kind of enhancement first. If you see turquoise objects marked as ‘stabilized’ stone, that means the soft, low-grade turquoise has gone through a special process that enhances its color and hardness.

The process involves putting the stone under pressure so that it absorbs a type of clear filler, either made of epoxy or plastic. The result: a harder stone that can actually be manipulated and cut. But because it’s treated turquoise, it’s not super valuable.

There are other types of cheap turquoise that you may have spotted in gift shops. Reconstituted turquoise (aka chalk turquoise) is made up of fragments of stones that are crushed into a powder and mixed with epoxy. This results in harder blocks that can then be cut into slabs or stone shapes.

Then there’s the fake stuff: Block or imitation turquoise is usually made of dyed plastic or produced by manipulating another stone like howlite so that it looks like turquoise.

Navigating the Turquoise Market

“Over 90 percent of the ‘turquoise’ on the world market has been stabilized, treated, or tampered with to enhance the color or harden the stone,” the Tanners write. “Some of the ‘turquoise’ on the market isn’t even turquoise at all, but an imitation material that has been dyed or colored to look like the stone. We always encourage anyone looking to purchase turquoise or turquoise jewelry to ask questions about the stones and forever say, ‘If you don’t know your turquoise, know your turquoise dealer.’ Natural gem quality turquoise is one of the most rare and collectable natural commodities of our world. It is indeed a special stone and one to be collected and celebrated.”

According to Otteson, the grade makes all the difference in determining the stone’s overall value. Like other gemstones, turquoise gems are graded according to criteria including the 4Cs — color, clarity, cut and carat weight — but they also have other unique factors to consider, like the location of its origin.

“On average, less than 25 percent of turquoise mined at our mines or any other mines, are used in jewelry, and only the top 4-5 percent of that turquoise is considered ‘gem grade,'” he says.

“‘Gem grade’ is a term commonly used among high-grade turquoise buyers and collectors to describe the heavily silicate, deep blue, spider web turquoise,” Otteson continues. “As a miner and a cutter, I have quickly learned to never get my hopes up too high when mining, because it’s hard to tell how good it is until it’s cut. Gem grade turquoise will take your breath away and send your heart rate off the charts.”

Turquoise: More Valuable Than Diamonds?

Despite the apparent abundance of turquoise, high quality stones are actually quite scarce — so scarce in fact that the best turquoise is “more valuable than diamonds.”

“Due to the fact that most mines have run dry and are now closed, compounded by government restrictions, and the high costs of mining; it has totally impeded the ability to find gem grade turquoise,” Otteson says. “All of these factors play a role in the value and appreciation found in a good turquoise nugget, and that’s what makes it so coveted.”

Otteson says that not only is really top-notch turquoise considered more valuable than diamonds, but it can be worth much more than other types of precious stones and metals that are often considered the most coveted jewelry staples.

“High-grade turquoise is worth three times the price of gold because it truly is that rare,” he says. “Most of the high grade mined in the ’60s and ’70s continues to trade hands between collectors and jewelers that truly understand its real value. Growing up in a mining family, I have learned to appreciate the difficulties of mining turquoise and the excitement of finding it.”